package oj;

import java.util.Scanner;

/**
 * @author 郝文雪
 * @date 2022/7/16 10:23
 * @Description Test
 */
public class Day18统计每个月兔子总数 {
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        int[] arr=new int[32];
        arr[1]=1;
        arr[2]=1;
        for(int i=3;i<arr.length;i++){
            arr[i]=arr[i-1]+arr[i-2];
        }
        while(sc.hasNext()){
            int n=sc.nextInt();
            int count=arr[n];
            System.out.println(count);
        }
    }
}
